/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jdbc.core;

import java.sql.ResultSet;
import java.sql.SQLException;
import javax.sql.rowset.CachedRowSet;
import javax.sql.rowset.RowSetFactory;
import javax.sql.rowset.RowSetProvider;

import org.springframework.jdbc.support.rowset.ResultSetWrappingSqlRowSet;
import org.springframework.jdbc.support.rowset.SqlRowSet;

/**
 * {@link ResultSetExtractor} implementation that returns a Spring {@link SqlRowSet}
 * representation for each given {@link ResultSet}.
 *
 * <p>The default implementation uses a standard JDBC CachedRowSet underneath.
 *
 * @author Juergen Hoeller
 * @see #newCachedRowSet
 * @see org.springframework.jdbc.support.rowset.SqlRowSet
 * @see JdbcTemplate#queryForRowSet(String)
 * @see javax.sql.rowset.CachedRowSet
 * @since 1.2
 */
public class SqlRowSetResultSetExtractor implements ResultSetExtractor<SqlRowSet> {

    private static final RowSetFactory rowSetFactory;

    static {
        try {
            rowSetFactory = RowSetProvider.newFactory();
        } catch (SQLException ex) {
            throw new IllegalStateException("Cannot create RowSetFactory through RowSetProvider", ex);
        }
    }


    @Override
    public SqlRowSet extractData(ResultSet rs) throws SQLException {
        return createSqlRowSet(rs);
    }

    /**
     * Create a {@link SqlRowSet} that wraps the given {@link ResultSet},
     * representing its data in a disconnected fashion.
     * <p>This implementation creates a Spring {@link ResultSetWrappingSqlRowSet}
     * instance that wraps a standard JDBC {@link CachedRowSet} instance.
     * Can be overridden to use a different implementation.
     *
     * @param rs the original ResultSet (connected)
     * @return the disconnected SqlRowSet
     * @throws SQLException if thrown by JDBC methods
     * @see #newCachedRowSet()
     * @see org.springframework.jdbc.support.rowset.ResultSetWrappingSqlRowSet
     */
    protected SqlRowSet createSqlRowSet(ResultSet rs) throws SQLException {
        CachedRowSet rowSet = newCachedRowSet();
        rowSet.populate(rs);
        return new ResultSetWrappingSqlRowSet(rowSet);
    }

    /**
     * Create a new {@link CachedRowSet} instance, to be populated by
     * the {@code createSqlRowSet} implementation.
     * <p>The default implementation uses JDBC 4.1's {@link RowSetFactory}.
     *
     * @return a new CachedRowSet instance
     * @throws SQLException if thrown by JDBC methods
     * @see #createSqlRowSet
     * @see RowSetProvider#newFactory()
     * @see RowSetFactory#createCachedRowSet()
     */
    protected CachedRowSet newCachedRowSet() throws SQLException {
        return rowSetFactory.createCachedRowSet();
    }

}
